clean before restore

[FuhuXia]

Add --if-exists --clean to the pg_restore option to get rid the following error. The error is more like a harmless warning but it does halt the script from completing.

pg_restore: while PROCESSING TOC:
pg_restore: from TOC entry 4; 2615 2200 SCHEMA public postgres
pg_restore: error: could not execute query: ERROR:  schema "public" already exists
Command was: CREATE SCHEMA public;